The Protein Associated with Hemolysin in Rabbit Serum and Plasma

1. The water-insoluble globulin with which hemolysin is associated, may be separated from immune serum or plasma by dilution and simple dialysis at optimal pH. 2. This optimum in plasma is influenced by the presence of the fibrinogen. 3. Fibrinogen carries no immune body, or only an insignificant amount; when present in immune body solutions in other form than fibrin gel, it depresses the hemolytic activity. The conditions for the formation of fibrin gel are similar to those for the formation of a gel by banana protein. 4. The hemolytic activity is a more labile property of the immune protein than the agglutinating activity; hemolysin is destroyed, hemagglutinin shows an apparent increase, as a result of alcohol extraction.